Easy Form Validation using HTML5

Writing validation logic using JavaScript in an HTML form is not easy. We all have seen it in HTML4 but what’s new in HTML5? Will it provide us with an easy way to validate a form by writing just a small piece of code?

Writing validation logic using JavaScript in an HTML form is not an easy
thing to do. We all have seen it in HTML4 but what’s new in HTML5? Will it provide us with
an easy
way to validate a form by writing just a small piece of code?

Today we will be talking about this validation stuff in HTML5. But as usual, all the browsers don’t support all of them but
it is a good start to think for future.

Introduction

In HTML4, we had a single input type for entering text but in HTML5 we have
different input types for entering different data types, e.g., we have email
data type for email address, url data type for entering a website
URL, number for numeric inputs, and text data type for strings.

Not only this, HTML5 also supports placing a watermark text as a place holder text of any textbox. This gives the page designer and user
an easy way to understand the input field.
You can remember that this was way too difficult in the earlier versions of HTML and even in ASP.NET.

As usual, HTML still has an issue in terms of browser support. HTML 5 is not yet standardized,
and all those features are not yet supported by all browsers.
Google Chrome and Firefox supports a vast number of features but IE is lacking
way behind.

Here is a comparison chart of HTML5 Validation support in different web browsers:

Look at the above chart and you will notice that IE support is still missing. I tested them in IE 10 and it’s working there but
is not yet confirmed in the browser compatibility chart.

Playing with code

To do easy validation using HTML5, you need to add support for HTML5 in your page by adding this line first at the top of the page:

<!DOCTYPEhtml>

Now you can choose between the various data types to include in the form. Here is a code snippet where we
have used the “text”, “email”, “url” and “number” data types to demonstrate this feature:

Check out the use of “placeholder” in the above code. It works just like a watermark text in the input textbox and provides
the user the necessary information while empty. The required attribute asks the user to enter text and on validation fail, it marks the textbox in red and shows a styled tooltip in the screen to enter some valid text in that box.

Similarly, it always tests for proper data types and throws invalid input when the data type mismatches.
Another interesting thing is with the number input type. It creates
a range validation logic with min and max attributes and creates a numeric up-down field in the screen. This feature is not supported on all browsers
and you will see a simple textbox in case it’s not supported by that browser.

End note

I hope that this quick little post will help you understand the basics of HTML5 form validation and if you are using HTML5, this will help you write less code
to do such big logic in your page.

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He is currently working in an MNC located in India. He has a very good skill over XAML, C#, Silverlight, Windows Phone, WPF and Windows Store (WinRT) app development. He posts his findings, articles, tutorials in his technical blog and CodeProject.

I used VS2012 to create a simple form for use on an Android. The VSNomad plugin compiled it ok and I sideloaded it by dropping the apx file into dropbox and installing from there on my phone. I started the app and poked the input to input a number and the keypad came up instead of the full keyboard. You made my day.